Impeller for centrifugal pump



June 30, 1964 M. AMIRAULT ETAL IMPELLER FOR CENTRIFUGAL PUMP 2Sheets-Sheet 1 Filed March 1, 1962 June 30, 1964 M. AMIRAULT EIAL3,139,034

IMPELLER FOR CENTRIFUGAL PUMP Filed March 1, 1962 2 Sheets-Sheet 2United States Patent Ofitice 3,139,034 Patented June 30, 1964 3,139,034IMPELLER FOR CENTRIFUGAL PUMP Maxime Amirault, 32, Ave. Le Notre,Sceaux, and Paul Destoumieux, 16, Ave. Sainte Foy, Neuilly-sur-Seine,

France Filed Mar. 1, 1962, Ser. No. 176,629 Claims priority, applicationFrance June 17, 1961 4 Claims. (Cl. 103-115) This invention relates toimprovements in the design and methods of manufacturing impellers orturbines of fans or centrifugal pumps with a view to improve theefficiency of these apparatus while reducing their cost.

These improvements are intended more particularly for small pumpsmanufactured on a relatively large scale, such as those utilized forcirculating water in the cooling system of automobiles or in laundrywashers. In pumps of this type it is current practice to manufacture theimpellers by pressing relatively thin sheet metal blanks. These partsare very economical to manufacture but the efficiency of hitherto knowndesigns is not particularly good, notably in the case of large-diameterimpellers driven at high rotational speeds.

It is the essential object of this invention to avoid this drawback byproviding an impeller designed and constructed with a view, for the sameimpeller dimensions and velocity of rotation, to yield a higherpressure, a greater output, a lower power consumption and thesuppression of vibration caused by cavitation phenomena.

The impeller or turbine according to this invention consists of arelatively thin sheet or disc formed with a central aperture formounting the impeller on a shaft and with substantially radialcorrugations about said aperture to provide alternate projecting sectorsand hollow sectors on both faces, and is characterized in that thesectors forming cavities on one of the faces which is to constitute thedownstream face are formed with arcuate apertures surrounding saidcentral aperture.

The impeller is mounted with this downstream face registering with thepump outlet or delivery side of the pump, and said arcuate apertures,while practically suppressing the bottoms of the vane-forming hollowsectors which are concentric with the impeller axis, provide about thepump shaft a passage for the circulation of fluid through these sectorsof which the solid peripheral portions counteract this flow.

The specific features and advantages of this invention will appear morecompletely from the following description of a few typical embodimentsthereof which are given by way of example with reference to theaccompanying drawings in which:

FIGURE 1 is an axial section illustrating diagrammatically a centrifugalpump equipped with the impeller or turbine of this invention;

FIGURE 2 is a front elevational view of the impeller as seen in thedirection of the arrows IIII of FIG. 1;

FIGURE 3 is a sectional development of the outer peripheral portion ofthe impeller;

FIGURE 4 is a diagrammatical axial section showing a typical tool forpressing from a punched or cut blank the impeller of FIGS. 1 to 3;

FIGURES 5 to 9 are views similar to FIG. 2 but showing alternateembodiments of the impeller of this invention; and

FIGURES 10 and 11 are views similar to FIG. 1 showing other possibleembodiments of the impeller.

The centrifugal pump impeller or turbine illustrated in FIGS. 1 to 3 ofthe drawing comprises a flange 1 secured on a hub 2 rigid in turn withthe pump shaft 3. The flange 1 consists of a relatively thin sheet metalblank pressed to form on either side vanes a, b, c and d, e, f of whichthe peripheral development is illustrated in FIG. 3. At the bottom ofvanes a, b and c, on the side opposite to the fluid inlet as shown bythe arrow F, apertures g are formed to permit the passage of the fluidtherethrough. Under the influence of the centrifugal force developed bythe rotation of the impeller the fluid is attracted both by the vanes d,e and f on the side F along the path shown by the arrow i, and by thevanes a, b and 0 formed on the other side, the fluid penetrating intoeach vane through its aperture g as shown by the arrow Experience provesthat the operation of this impeller having a double operating face isvery satisfactory in that its output and pressure efficiency isextremely high and that it does not vibrate, and requires less power forits operation. Another substantial advantage of the impeller accordingto this invention is its very low cost. In fact, the flange may bemanufactured very easily by pressing a blank that can be cut withoutdifiiculty from relatively thin metal-sheet stock, althoughthermosetting plastic materials may also be used with satisfactoryresults. Furthermore, this part can be moulded from any suitablematerial such as metal, Bakelite, natural and synthetic rubber,injection-moulded or sheet plastics, etc., by using a mould consistingof only two sections, shells or halves. In fact, the inner edge of theapertured vanes has a diameter equal to or slightly greater than theaperture formed in the flange so that a two-section pressing or mouldingtool 5, 6 can be used without difficulty, as shown in FIG. 4. In thisfigure it is assumed that the impeller is manufactured by pressing apre-cut blank in which the central aperture and the spaced arcuate apertures g are formed beforehand. f it is desired to manufacture the partby moulding a suitable plastic material, the contacting surfaces of thetwo halves 5, 6 of the tool or mould are simply modified accordingly, sothat these surfaces may interfit exactly and contact each other insidethe contour of these apertures.

The impeller described hereinabove is formed with radial vanes but itwill be readily understood by anybody conversant with the art that othershapes may be imparted thereto without departing from the spirit andscope of the invention, for example by inclining the vanes in relationto the radial direction, as shown in FIG. 5, or imparting thereto acurved configuration in one or the other direction, as shown in FIGS. 6,7 or 8, with a view to improve the pressure or the output, or forreducing the power consumption. It will be noted that. the impellerillustrated comprises only three vanes, but this number is given only byway of example to simplify the drawing for 2, 4, 5, 6 or more vanes maybe provided without departing from the spirit and scope of theinvention. The vanes illustrated have also the same contour and capacityon both sides and on the two opposite faces of the flange, but it wouldnot constitute a departure from the basic principles of this inventionto provide vanes having different characteristics either from oneanother on the same face or from one face to the other. It may also benoted that the impeller illustrated in FIGS. 1 and 2 is of the typeadjustable laterally against the pump body 4, but as shown in FIG. 10 itis also possible to fit on one or both faces of the impeller acollar-forming flange K to permit a cylindrical fitting. Still withinthe scope of this invention, an impeller of the type illustrated in FIG.11 may be provided wherein the flange 1a is formed on one face with afrusto-conical marginal portion 11 registering with a corresponding faceof the pump body 4a.

According to an alternate embodiment of this invention, the aperturesmay extend symmetrically as shown in FIGS. 2 and 9, or asymmetrically,according to the direction of rotation, in order to facilitate thepassage of fluid along the surface of the vanes located on the sideopposite to the fluid inlet, as in the cases illustrated in FIGS. 5

to 8, but other shapes may also be used if desired. To the same end, andwithout departing from the spirit and scope of the invention, it is alsopossible to provide apertures having their edges coincident with thevanes on a diameter considerably smaller than that of the edge locatedon the other face of the flange. With this arrangement the mouldingoperation is more difficult than in the preceding case, but thisincreased difiiculty is compensated by a substantial improvement in theover-all efficiency of the impeller.

The hub formed or not integrally with the flange may also be an integralpart of another element, for example a fluid seal; besides, the flangemay also be secured directly on the shaft.

Although the present invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention, as those skilled in the art will readilyunderstand' Such modifications and variations are considered to bewithin the purview and scope of the invention and appended claims.

What we claim is:

1. A centrifugal pump impeller having an upstream face and an oppositedownstream face and causing, when rotatably driven, a fluid to flowaxially from said upstream face to said downstream face, said impellerbeing particularly suitable for a pump of relatively small size andconsisting of a circular plate having formed therethrough a centralcircular mounting aperture and arcuate slots disposed at spacedintervals around a circle concentric to said circular aperture, saidcircle bounding in the plate a central flat portion and an outer portioncomprising a first series of sectors extending radially from said slotsand another series of sectors interlocked with the sectors of the firstseries, the sectors of one series being axially shifted in a directionfrom the central flat portion of the circular plate and the sectors ofthe other series being axially shifted in the opposite direction at thesame distance from the central flat portion of the circular plate,

the plate face from which the sectors of the first series protruderelative to the central fiat portion forming the upstream face of theimpeller and the sectors of the other series forming the downstream faceof the impeller.

2. A centrifugal pump impeller having an upstream face and a downstreamface and causing, when it is rotatably driven, the axial flow of aliquid from said upstream face to said downstream face, said impellerconsisting of a circular plate formed with a central hole bounded by acircular edge and comprising an inner annular zone extending around thecircular edge of said central hole up to an intermediate circleconcentric to said central hole and an outer circular zone extendingaround said intermediate circle, said circular plate being furtherformed with slots in the form of circular arcs disposed at spacedintervals along said intermediate circle, the ends of the adjacent slotsforming along said intermediate circle solid gaps having the sameangular amplitude as said slots, said inner circular zone being offrustoconical configuration opening into the downstream face with arelatively wide angle, said intermediate circle being therefore disposedwith an axial downstream shift in relation to the circular edge of saidcentral hole, said outer circular zone comprising upstream sectorsextending radially beyond said arcuated slots and said intermediatedownstream sectors, the upstream sectors being shifted axially upstreamin relation to the downstream sectors, said downstream sectors extendingin the plane of said intermediate circle and said upstream sectorsmerging into said downstream sectors through radial planes coincidentwith the ends of said slots.

3. A pump impeller as set forth in claim 2, wherein said upstream axialshift of said upstream sectors in relation to said downstream sectors istwice the axial shift of said downstream sectors in relation to thecircular edge of said central hole.

4. A pump impeller as set forth in claim 2, used in combination with arotary shaft and a casing having flat inner walls extending at rightangles to said shaft, said impeller being rigidly mounted on said shaftby means of its central hole in the space available between said twoflat inner walls of said casing, wherein said upstream axial shift ofsaid upstream sectors in relation to said downstream sectors is slightlyinferior to the relative spacing of said flat inner walls of saidcasing.

References Cited in the file of this patent UNITED STATES PATENTS929,129 Harder July 27, 1909 1,131,294 Traylor Mar. 9, 1915 1,867,290Vitu July 12, 1932 2,540,136 Oliphant Feb. 6, 1951 2,831,630 Perry Apr.22, 1958 FOREIGN PATENTS 1,237,308 France June 20, 1960 8,454 GreatBritain of 1910 250,542 Great Britain of 1927 419,252 Great Britain Nov.8, 1934

1. A CENTRIFUGAL PUMP IMPELLER HAVING AN UPSTREAM FACE AND AN OPPOSITEDOWNSTREAM FACE AND CAUSING, WHEN ROTATABLY DRIVEN, A FLUID TO FLOWAXIALLY FROM SAID UPSTREAM FACE TO SAID DOWNSTREAM FACE, SAID IMPELLERBEING PARTICULARLY SUITABLE FOR A PUMP OF RELATIVELY SMALL SIZE ANDCONSISTING OF A CIRCULAR PLATE HAVING FORMED THERETHROUGH A CENTRALCIRCULAR MOUNTING APERTURE AND ARCUATE SLOTS DISPOSED AT SPACEDINTERVALS AROUND A CIRCLE CONCENTRIC TO SAID CIRCULAR APERTURE, SAIDCIRCLE BOUNDING IN THE PLATE A CENTRAL FLAT PORTION AND AN OUTER PORTIONCOMPRISING A FIRST SERIES OF SECTORS EXTENDING RADIALLY FROM SAID SLOTSAND ANOTHER SERIES OF SECTORS INTERLOCKED WITH THE SECTORS OF THE FIRSTSERIES, THE SECTORS OF ONE SERIES BEING AXIALLY SHIFTED IN A DIRECTIONFROM THE CENTRAL FLAT PORTION OF THE CIRCULAR PLATE AND THE SECTORS OFTHE OTHER SERIES BEING AXIALLY SHIFTED IN THE OPPOSITE DIRECTION AT THESAME DISTANCE FROM THE CENTRAL FLAT PORTION OF THE CIRCULAR PLATE, THEPLATE FACE FROM WHICH THE SECTORS OF THE FIRST SERIES PROTRUDE RELATIVETO THE CENTRAL FLAT PORTION FORMING THE UPSTREAM FACE OF THE IMPELLERAND THE SECTORS OF THE OTHER SERIES FORMING THE DOWNSTREAM FACE OF THEIMPELLER.